Vascular supply (Circle of Willis) — Flashcards

Flashcard 1: What structure is most commonly compressed by an aneurysm of the anterior communicating artery?

Answer: Optic chiasm compression, resulting in bitemporal hemianopia.

Extra: Aneurysms of the anterior communicating artery (ACom) are the most common site of Berry aneurysms in the Circle of Willis. Due to their location, they can compress the optic chiasm, leading to visual field defects.

Flashcard 2: An aneurysm of which artery is most commonly associated with a CN III palsy?

Answer: CN III (Oculomotor nerve) palsy

Extra: Aneurysms of the posterior communicating artery (PCoA) typically cause a CN III palsy with pupil involvement (mydriasis), because the parasympathetic fibers are superficial on the nerve. Findings: Ptosis, "down and out" eye position, and a dilated pupil.

Flashcard 3: Where do saccular "berry" aneurysms tend to occur?

Answer: bifurcations in Circle of Willis; especially anterior and posterior communicating arteries

Flashcard 4: Identify the branch of the vertebral artery labeled as number 3 in the provided image.

Answer: posterior spinal arteries

Flashcard 5: Identify the artery in the vertebrobasilar system labeled as number 9 (the vessel formed by the union of branches from both vertebral arteries descending the spinal cord):

Answer: Anterior spinal artery

Extra: The anterior spinal artery is formed by the union of two small branches from the vertebral arteries. It descends in the anterior median fissure and supplies the anterior two-thirds of the spinal cord.

Flashcard 6: anterior cerebral artery (ACA)

Answer: medial motor cortex, medial sensory cortex

Extra: leg paralysis and sensory loss

Flashcard 7: Most common site of Berry (saccular) aneurysm in the Circle of Willis?

Answer: Anterior communicating artery (ACoA) junction

Extra: Berry (saccular) aneurysms are most common at the ACoA (approx. 40%). They are associated with ADPKD, Ehlers-Danlos syndrome, and Marfan syndrome. Rupture leads to subarachnoid hemorrhage.

Flashcard 8: anterior inferior cerebellar artery (AICA)

Answer: lateral pons, cerebellar peduncles

Extra: vomiting, vertigo, nystagmus, facial paralysis, facial sensory loss, Horner's syndrome, ataxia, dysmetria decreased: lacrimation, taste, corneal reflex, hearing

Flashcard 9: What is the underlying pathology of a Berry (Saccular) aneurysm?

Answer: Congenital defect in the tunica media at vessel bifurcations.

Extra: - Most common site: Anterior communicating artery (ACom). - Clinical Presentation: Subarachnoid hemorrhage ("worst headache of life") or bitemporal hemianopsia (compression of optic chiasm by ACom aneurysm). - Risk factors: ADPKD, Ehlers-Danlos syndrome, Marfan syndrome, HTN, smoking, advanced age, African American race.

Flashcard 10: posterior cerebral artery

Answer: posterior and inferior surfaces

Extra: blue region